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Survey: How Much Do U.S. Residents Know About Rare Diseases?

A new survey of more than 1,000 U.S. residents finds that few know how common rare diseases are, but 85% said it was important to research innovative new treatments.

85% of U.S. respondents said it was important to research rare diseases and invest in making innovative treatments accessible to patients.

A new survey commissioned by CSL ahead of Rare Disease Day (February 29) found that most U.S. adults don’t know the full impact of rare diseases, with many believing they affect far fewer people than they do: 300 million worldwide.

Of 1,073 U.S. adults surveyed this month, 50% of respondents thought the number was between 300,000 and 3 million. The U.S. defines a rare disease as a condition that impacts fewer than 200,000 Americans – another fact that eluded 81% of survey participants. Less than one in five respondents (17%) said they knew someone with a rare condition.

Only 10% of survey respondents knew that more than 7,000 rare diseases have been identified. Presented with a list of seven rare diseases, just over  a quarter (26%) of survey respondents said they had not heard of any of them. 

56% of U.S. respondents had heard of hemophilia

Just more than half (56%) said they had heard of hemophilia, a bleeding disorder and 20% had heard of primary immunodeficiency, a group of diseases related to an impaired immune system. Eleven percent or less knew of von Willebrand Disease (11%); Hereditary Angioedema (HAE) (11%); Chronic Inflammatory Demyelinating Polyneuropathy (CIDP) (11%); ANCA-associated vasculitis (4%); and Alpha 1 Antitrypsin Deficiency (7%).

20% of U.S. respondents had heard of primary immunodeficiency

The results among the general public are not surprising. Even medical schools have identified a  knowledge gap about rare diseases among doctors in training and have launched programs to address it.

Making the public more aware of rare diseases can help patients who struggle with undiagnosed conditions, but it’s daunting because there are so many different conditions – most of which lack treatments. It can take years to get an accurate diagnosis and, even once they are diagnosed, rare disease patients can feel isolated without an easy route to find a community. 

81% of U.S. respondents said the health care system should do more to support people who have rare diseases.

Organizations like the National Organization for Rare Disorders help unite patients and advocates from many rare disease communities. CSL, a global biotech, makes medicines that treat rare diseases and participates annually in Rare Disease Day events, including the Black Pearl Awards and the Global Chain of Lights.

Only 13% of survey respondents had heard of Rare Disease Day, celebrated on Leap Day this year, the rarest calendar day. Though the survey found knowledge gaps among U.S. adults, a majority of participants voiced support for patients who live with rare conditions.

82% of U.S. respondents agreed that it's important to give rare disease patients an opportunity to share their experiences.

More than 80% agreed with these statements:

  • Our health system should do more to support people with rare diseases. (81%)
  • It’s important that we research rare diseases and invest in making innovative treatments accessible to people. (85%)
  • It’s important that we give people with rare diseases an opportunity to share their experiences. (82%)

CSL commissioned the same survey in Australia, where results were similar. See the Australian results. 

The U.S. survey was conducted by YouGov on behalf of CSL. All figures, unless otherwise stated, are from YouGov Plc. Total sample size was 1,073 U.S. adults aged 18+. Fieldwork was undertaken in February 2024. The survey was carried out online. The figures have been weighted and are representative of U.S. adults (aged 18+).